water changes: how much

[bjledbetter]

I have a 90g tank with a 40g sump/fuge that holds maybe 20g of water. I am battleing canyo/dinos not sure really which,and a small alage problem and think it may be due to not doing big enough water changes. Right now im doing 10g a week which i figure is 20% bi weekly total water being chaned. Should I do a bigger cwc at one time say maybe 20g a week? what would you reccomend for a wc on a 90?

 

[mattgreene22]

what fish and corals are you keeping? what and how much are you feeding? how good is your skimmer? what are you using for flow in your display? how old are your bulbs? have you tested your water lately?

Just asking what I figure others will want to know...

Also, I would describe what you're doing now more as 9% weekly...and understand your taking out some week old water in addition to older water on the second water change. It's less than 20% biweekly. You may still be fine (the percentage differences aren't large) and its something else entirely, but if you want to exchange a little bit more volume then perhaps you do 20g biweekly and you won't be making any more saltwater than you are now. Or, keep with the more frequent water changes and up it a little bit. How well does your new saltwater match with existing display tank parameters? If not close, then perhaps you're regularly moving your displays parameter out of line and your tank is responding to a certain degree of instability.

 

[dirtycontour]

I change enough to siphon out as much detritus as possible. That translates to about 10% weekly.

 

[Kano]

When I was running my 90g I did 10-15 gallons per week. Sometimes it'd go past a week but typically weekly. If you're having issues up the amount by a few gallons and make sure the water you're adding is actually clean water. If you're getting your water from a LFS ask what the TDS is and how often they check it. Same if you get it from a local water store. A store by me has the TDS at 3-4 and he checks it daily (has a log and everything). I've been using it over a year without issues so far. If they won't tell you or don't know find a new source.

 

[bjledbetter]

Fish: a pair of occ. clowns a pair of clarki clowns (and yes eventually they will be seperated).A breeding pair of yellowtail blue damsels and a pair of 4 stripe damsels.
Corals: Frogspawn, Gsp,Rbta,Ritteri anemone, xenia, blastomussa meretti, toadstool, and some zoas
Feeding: spectrum pellets and krill for the nems
Flow koralle nano, and two pumps from petco. there is quite a bit as one is quite large.
Skimmer is a Reef octopus rated for 100 gallon (it was the biggest I could afford at the time)
Lighting : 2x 250w 14k phoneix mh 4 months old, evolution 200 led fixture
Water parameters. Nitrates, ammonia 0 per salfret at lfs tested weekly, Alk 10.5 Ph 8.6 per red sea at home weekly CA and Mag are both high and I cant get them to come down.
Water comes from lfs and is the only place around to get ro water,even though i never had this mess when I was using just tap water. Ive never asked for tds. Im going to start doing 20 biweekly and see if that helps any

 

[Crystal03JC]

We have a 90 and change almost 10% weekly, seems to work for us

 

[Isoprene]

I dont think your issue is the WC's. Id look for some other problem, WC will only help the algae, cyano problem your discussing temporarily, you need to find the source:

mattgreene22 what fish and corals are you keeping? what and how much are you feeding? how good is your skimmer? what are you using for flow in your display? how old are your bulbs? have you tested your water lately?

 

[bjledbetter]

I dont think your issue is the WC's. Id look for some other problem, WC will only help the algae, cyano problem your discussing temporarily, you need to find the source:

I posted what is in the tank/pram/lighting above. If its not the wc/water what could it be? My corals/fish/nems look fine and health this stuff just wont go away so i thought it was my water.

 

[bjledbetter]

I even changed salt mixes

 

[Peterock]

I have almost the same set up with 75g tank and 20g in the sump. I change 10-15g every 2-3 weeks with Kent salt and RO/DI <1 TDS.
Your bioload isn't a lot... I bet its the water you use.

How's your clean up crew?

 

[bjledbetter]

most of it died from eating that mess i think. I have like 10 snail left and 2 redleg hermits

 

[Isoprene]

Yeah what have you got for clean up crew? Also how much LR do you have? Is your skimmer producing "gunk" regularly? Do you have any Chaeto in your sump? Also flow might be the problem here. Those Petco power heads are worthless imo unless your using them to mix salt. Two have died on me just using them for that in the past year. Also how often are you feeding and how much of each? What kind of pump are you using in your sump gph? idk honestly just throwing out possibilities

just read your response, id get more snails, too many cant hurt if your having detritus and cyano problems.

 

[cultivatedcoral]

Your water may be the problem. If you do bigger water changes with the same water it may get worse. Are you getting ro/di water from your lfs? If so, check it for tds, phosphates and nitrates.

 

[Ron Reefman]

I have a 90g tank with a 40g sump/fuge that holds maybe 20g of water. I am battleing canyo/dinos not sure really which,and a small alage problem and think it may be due to not doing big enough water changes. Right now im doing 10g a week which i figure is 20% bi weekly total water being chaned. Should I do a bigger cwc at one time say maybe 20g a week? what would you reccomend for a wc on a 90?

How long has your tank been running? I don't think it's your water changes either. I have a 350g system and I do a 7-8% water change ever 4-6 weeks just to add trace elements. I think you may be overfeeding. Cyano likes carbon and still water, algae like nitrates and phosphates. You really need to figure out what it is you are fighting. Being "not really sure" really doesn't make your job any easier. What does it look like? What color is it? Where is it growing? Can you post a pic or 2?

 

[Isoprene]

+1 ^

 

[beaslbob]

Kill the lights, stop adding food until the cyano dies off.

then resume with less lighting and feeding so your corraline, macro algae, corals thrive but not the cyano.